The Industar-61 lens was designed by Soviet opticians V. Sokolova and G. Slyusarev. It was the first Soviet lens for the consumer segment to use lanthanum optical glass. Industar-61 was intended to replace the outdated Industar-26m 50/2.8 and become an intermediate link between the cheap Soviet “whale” Industar-50 50/3.5 and the more expensive high-aperture Helios-44 58/2 (or Jupiter-8 50/2, if we speak about rangefinder cameras). In fact, Industar-61 turned out to be very technologically advanced and popular; countless numbers of it were produced in different design options and body designs, at different enterprises.
The review presents a rare early version of the lens - Industar-61L, intended for use with rangefinder cameras with an M39 mount thread. In this case, the letter L means the place of production - the Lytkarino Optical Glass Plant, although it is generally accepted that, for example, in Industar-61L/D produced by FED, the same letter indicates the use of lanthanum in lenses. Indeed, the use of rare earth glasses was sometimes reflected in the name, for example, Voightlander Lanthar. This was a good marketing move, since lanthanum lenses made it possible to significantly improve the quality of simple three- and four-element lenses, which was appreciated by the consumer.
Technical characteristics
Optical design - “Tessar”, 4 lenses in 3 groups (Yakovlev’s reference book, vol. 1),
Focal length – 52.42 mm;
Relative aperture – 1:2.8;
Frame format – 36*24 mm;
Aperture – 12 blades, without preset mechanism;
Aperture limits – F/2.8-F/16;
Minimum focusing distance – 1 m;
Thread for filters – 33 mm;
Diameter for smooth nozzles – 36 mm;
Mounting – M39*28.8 mm;
Weight – 130 g.